package three.day.frame;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calc2 extends JFrame{
private JLabel lbNum1;
private JLabel lbNum2;
private JTextField tfNUm1;
private JTextField tfNUm2;
private JLabel tfPlus;
private JLabel tfEquals;
private JTextField tfResult;
private JButton btSimmit;
private JButton btReset;
private JPanel panel;
private double num1;
private double result;
public Calc2(String title) throws HeadlessException {
super(title);
Container cp = getContentPane();
cp.setLayout(new BorderLayout());
panel = new JPanel();
panel.setLayout(new FlowLayout());
lbNum1 = new JLabel("输入一个数");
lbNum2 = new JLabel("输入一个数");
tfPlus = new JLabel("输入一个数");
tfEquals = new JLabel("输入一个数");
tfNUm1 = new JTextField(15);
tfNUm2 = new JTextField(15);
tfResult = new JTextField(15);
tfResult.setBackground(Color.yellow);
btSimmit = new JButton("计算");
btSimmit.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent arg0) {
String str = tfNUm1.getText();
if(str.equals("")){
JOptionPane.showMessageDialog(Calc2.this, "你没有输入数值，请重新输入", "警告", JOptionPane.WARNING_MESSAGE);
return;
}
else{
try {
num1 = Double.valueOf(str);
result = Math.pow(num1, 2);
} catch (NumberFormatException e) {
e.printStackTrace();
tfResult.setText("");
JOptionPane.showMessageDialog(Calc2.this, "你的输入有异常，请重新输入", "警告", JOptionPane.WARNING_MESSAGE);
return;
}
}
tfResult.setText(String.valueOf(result));
}
});
btReset = new JButton("重置");
btReset.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
tfNUm1.setText("");
tfResult.setText("");
}
});
panel.add(lbNum1);
panel.add(tfNUm1);
panel.add(btSimmit);
panel.add(btReset);
panel.add(tfResult);
cp.add(panel,BorderLayout.CENTER);
setVisible(true);
setSize(600,150);
setLocation(250,200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new Calc2("我的计算器");
}
}